The technology for inserting digital watermarks in documents and the technology for detecting and reading digital watermarks that are embedded in documents is well developed. Furthermore, methods and systems for linking to internet sites in response to physical objects that contain watermarks are known. For example see co-pending application Ser. No. 09/571,422 May 15, 2000 entitled “Methods and Systems for Controlling Computers or Linking to Internet Resources from Physical and Electronic Objects” the content of which is hereby incorporated herein by reference.
It is also noted that a system marketed by Digimarc Corporation under the trademark “Media-Bridge” includes a central computer which accepts and registers identification numbers and associated action strings, and software which reads a watermark containing an identification number. When a watermark is read, the data base is interrogated via the Internet to locate a previously registered action string, and a response is returned to the requesting software via the Internet.
In some situations, the turn around time between when a watermark is read and when a desired action occurs is very critical. For example, watermarks on a ticket for an event can be used to carry authentication data. The data carried by the watermark on the ticket can be compared to data registered on a server in order to authenticate the ticket. When a ticket is presented at an entry point for an event, the ticket must be authenticated very quickly. The present invention provides a system which can be used to very quickly authenticate documents such as tickets through a local area or a wide area network. The authentication is done without the use of communication via the Internet. Tickets may be sold at many different locations, hence, identification data is registered at a central site using the Internet. At a specified time, the registration data is downloaded to a computer data base at a local site where the tickets will be presented for entry to an event. At the time of the event, when the tickets are presented for authentication, the identification is done quickly for the local data base via a local area network (LAN). Data for tickets sold after the initial download can be downloaded as increments to the local data base.
In other situations, for security considerations, it is not desirable to store all the registration data in a single local data base. In one embodiment, the present invention provides a number of local computers which exchange data on a peer to peer basis. Thus the data can be compartmentalized for security reasons.
In still other situations, due to security and other considerations, it is desirable that all communication be over a local area or wide area network other than the Internet. The present invention provides a system that can operate on a local area network (LAN) or on a wide area network (WAN).